1. Field of the Invention
The present invention relates to an organic EL device and a method for manufacturing the same.
2. Description of Related Art
Organic EL devices are recently used in various industrial fields, for example, a back light device of a liquid crystal display (LCD) device, a portable terminal apparatus, an automobile navigator, a computer and a television, because of its rapid response speed, excellent brightness, simple structure, low production cost, and light weight, etc.
In order to configure the organic EL devices, first electrodes or transparent a electrodes are arranged on a thin transparent substrate, and an EL light-emitting layer that emits light by itself is disposed on the transparent electrodes before second electrodes are disposed on the EL light-emitting layer.
In the organic EL device having such a configuration, the transparent electrode has refractive index different from the substrate. Therefore, when light from the EL light-emitting layer passes through an interface between the transparent electrode and the substrate, light from the EL light-emitting layer is totally reflected due to the difference in the refractive index and is wave-guided to be lost. For example, the transparent electrode has a refractive index of about 1.8 to about 2.1, and the glass substrate has a refractive index of about 1.46. As a result, about 51% of light is lost while passing through an interface between the transparent electrode and the substrate, and about 31.5% of light is lost while passing through the substrate. Therefore, only 17.5% of light is viewed by observer.
17.5% of light is too low to display images. In order to compensate the reduced amount of light, more current is applied to the EL light-emitting layer because light from the EL light-emitting layer is proportional to the current intensity. Even though such a method can boost light amount, however, higher intensity of current reduces the life span of the EL light-emitting layer and increases power consumption.
To overcome the problems described above, preferred embodiments of the present invention provide an organic EL device having a high brightness.
It is another object of the present invention to provide an organic EL device of long life span.
It is also another object of the present invention to provide an organic EL device of low power consumption.
In order to achieve the above object, the preferred embodiments of the present invention provide an organic EL device, including a transparent substrate, at least one first electrodes disposed on the substrate, at least one conductive light reflecting layer disposed to cover at least one of side portions of the first electrode, at least one EL light-emitting layer disposed on the first electrode and generating light having a predetermined wavelength, and at least one second electrode disposed on the EL light-emitting layer.
The preferred embodiment of the present invention further provides an organic EL device, including a transparent substrate having a display region with a pixel region, first electrodes disposed on the display region of the substrate in a first direction and spaced apart from each other, conductive light reflecting layers disposed to expose top portions of the first electrode according to the pixel region of the substrate and covering both side portion of the first electrode parallel to the first direction, EL light-emitting layers disposed on the top portions of the first electrode according to the pixel region, and second electrodes disposed in a second direction perpendicular to the first direction while covering the EL light-emitting layers.
The preferred embodiment of the present invention further provides an organic EL device, including a transparent substrate, first electrodes having electrode patterns disposed in the form of a matrix, conductive light reflecting layers electrically connecting corresponding to electrode patterns to define the first electrode and exposing top portions of the electrode patterns of the first electrodes, EL light-emitting layers as disposed on the top portions of the electrode patterns of the first electrodes, and second electrodes disposed on the EL light-emitting layers and in a perpendicular direction to the first electrodes.
The preferred embodiment of the present invention further provides an organic EL device, including a transparent substrate, first electrodes having first electrode portions and second electrode portions, the first electrode portions being wider than the second electrode portions, conductive light reflecting layers disposed to cover at least one of side portions of the first electrodes, EL light-emitting layers disposed on the first electrode portions of the first electrodes, and second electrodes disposed on the EL light-emitting layers and in a perpendicular direction to the first electrodes.
The two conductive light reflecting layers are disposed to cover both side portions of the first electrodes. The conductive light reflecting layer is disposed to cover all side portions of the first electrodes. The conductive light reflecting layer is formed by either depositing or plating a metal layer. The device further includes an insulating layer disposed between the adjacent two first electrodes while covering the conductive light reflecting layer. The first electrodes have a beehive shape.
The preferred embodiment of the present invention provides a method for manufacturing an organic EL device having a transparent substrate having a display region, the display region having pixel regions, including forming first electrodes on the display region of the transparent substrate, forming conductive light reflecting layer to cover at least one side portion of the first electrodes, forming EL light-emitting layers on portions of the first electrodes corresponding to the pixel regions, and forming second electrodes disposed in a perpendicular direction to the first electrodes while covering the EL light-emitting layers.
The preferred embodiment of the present invention provides a method for manufacturing an organic EL device, including forming matrix-shaped first electrodes having electrode patterns on a transparent substrate, forming conductive light reflecting layer connecting the corresponding electrode patterns to define the first electrode and exposing top portions of the electrode patterns of the first electrodes, forming EL light-emitting layers on the top portions of the first electrodes, and forming second electrodes disposed in a perpendicular direction to the first electrodes and covering the EL light-emitting layers.
The method further includes forming insulating layers between the adjacent two first electrodes while covering the conductive light reflecting layer. The step of forming the conductive light reflecting layers includes depositing a metal layer over the whole surface while covering the first electrodes, and patterning the metal layer into the conductive light reflecting layers. The step of forming the conductive light reflecting layer includes, plating at least one side portion of the first electrode with a metal layer by immersing the substrate on which the first electrodes are formed into an electrobath filled with electrolyte. The first electrodes have first electrode portions and second electrode portions, the first electrode portion being wider than the second electrode portions. The EL light-emitting layer is formed on a top portion of the first electrode portion of the first electrode.
An organic EL device of higher brightness, longer life span, and lower power consumption can be manufactured.